The present invention relates to an electromagnetic-induction coupling apparatus adapted for use as a feeder system for supplying electric power to a spherical semiconductor by electromagnetic-induction coupling with a coil for use as an antenna element on the peripheral surface of the spherical semiconductor by means of the coil and/or a data communication system for transmitting to and receiving information signals from the spherical semiconductor.
Recently, there have been proposed spherical semiconductors that have functional elements, such as a transistor, sensor, etc., and a semiconductor integrated circuit for predetermined processing functions formed on the surface of a spherical semiconductor chip (ball) with a diameter of about 1 mm. Usually, one such spherical semiconductor comprises a coil (loop antenna) 2 that functions as an antenna element on the surface of a spherical semiconductor chip 1, as shown in FIG. 10. Utilizing electromagnetic-induction coupling by means of a coil 2, the spherical semiconductor is configured to be actuated by external electric power supply and to transmit to and receive information signals from an external apparatus through the coil.
The integrated circuit that is formed on the semiconductor chip 1 comprises a power source unit 3 that receives electric power (electromagnetic energy) externally fed through the coil 2, thereby forming an internal power source, a receiver unit 4 that receives the information signals from the external apparatus through the coil 2, and a transmitter unit 5 that transmits the information signals to the external apparatus through the coil 2, as shown in FIG. 11, for example. Further, the integrated circuit comprises a sensor unit 7 such as a temperature sensing element, a memory 8, etc., as well as an apparatus body 6 formed of an arithmetic and control unit or the like, and is configured to fulfill given functions based on the operation of the apparatus body 6.
The transmission and reception of the information signals through the coil 2 are carried out by, for example, modulating the information signals with use of an electromagnetic-induction magnetic field for transmitting electric power as a carrier.
On the other hand, a feeder system for externally supplying electric power to the aforesaid spherical semiconductor by utilizing electromagnetic-induction coupling with the coil 2 and a data communication system for transmitting to and receiving the information signals from the spherical semiconductor through the coil 2 are realized as an electromagnetic-induction coupling apparatus with a coil that forms an electromagnetic-induction magnetic field in a region to which the spherical semiconductor is guided. More specifically, this electromagnetic-induction coupling apparatus (feeder/data communication system) is provided with a coil 9 for use a looped antenna, as shown in FIG. 12, and is configured to form by means of the coil 9 the electromagnetic-induction magnetic field in the region (coupling region) to which the spherical semiconductor is guided.
However, the posture of the spherical semiconductor that is guided to the coupling region near the coil 9 in which the electromagnetic-induction magnetic field is formed by means of the coil 9 is not always uniform, and its direction is generally irregular on account of its spherical shape. As mentioned before, on the other hand, the coupling region to which the spherical semiconductor is guided is located near the coil 9, so that the direction of a magnetic field H in the coupling region is perpendicular to the loop plane of the coil 9. As shown in FIG. 13, therefore, an angular deviation xcex8 is inevitably caused between the direction of the magnetic field H in the coupling region and the axial direction of the coil 2 on the spherical semiconductor.
This angular deviation xcex8 of the axial direction of the coil 2 from the direction of the magnetic field H causes the strength of coupling between the coil 2 and the magnetic field H, that is, the strength of electromagnetic-induction coupling, to change considerably. If the intensity of the magnetic field generated by means of the coil 9 of the electromagnetic-induction coupling apparatus is fixed, therefore, the intensity of the magnetic field to which the coil 2 of the spherical semiconductor is subjected substantially changes depending on the angular deviation xcex8, as shown in FIG. 14, for example. Since the electromagnetic-induction coupling with the coil 2 considerably lowers if the axial direction of the coil 2 is deviated by xcfx80/2(3xcfx80/2) or thereabout from the direction of the generated magnetic field H, malfunction may occur such that transmission and reception of the information signals are hindered or the aforesaid power supply is interrupted.
The object of the present invention is to provide an electromagnetic-induction coupling apparatus capable of easily effectively obviating the aforesaid malfunction so that electric power supply to a spherical semiconductor and transmission and reception of information signals can be carried out securely.
In other words, the object of the present invention is to an electromagnetic-induction coupling apparatus adapted to realize a feeder system capable of securely supplying electric power to a spherical semiconductor through a coil on the surface of the spherical semiconductor without regard to the posture of the spherical semiconductor, especially the direction of the coil, and/or a data communication system capable of securely transmitting to and receiving information signals from the spherical semiconductor through the coil.
More specifically, an electromagnetic-induction coupling apparatus according to the present invention supplies electric power to a spherical semiconductor having a looped coil on the surface thereof by electromagnetic-induction coupling by means of the coil and/or transfers information signals to and from the spherical semiconductor through the coil.
In order to achieve the above objects, in particular, the apparatus comprises a coil array including a plurality of coil elements two-dimensionally arranged on a given plane, and a magnetic field control element for controlling the respective polarities and phases of magnetic fields generated by means of the individual coil elements of the coil array, thereby changing the respective directions of magnetic fields in a region near the coil array to which the spherical semiconductor is guided.
The control system of the magnetic field control element is constructed so that the directions of the magnetic fields in the region near the coil array to which the spherical semiconductor is guided are successively changed in given cycles. Alternatively, the control system of the magnetic field control element is configured to monitor a response from the spherical semiconductor based on specific information communication and change the directions of the magnetic fields in the region near the coil array to which the spherical semiconductor is guided when no response is obtained from the spherical semiconductor in a given period.
The magnetic field control element drives a plurality of coil elements of the coil array in phase, thereby generating a magnetic field perpendicular to the coil plane of the coil array in the region near the coil array to which the spherical semiconductor is guided. Further, the magnetic field control element drives a plurality of coil elements in predetermined sets of the coil array out of phase, thereby generating a magnetic field parallel to the coil plane of the coil array or inclined at a given angle to the coil plane in the region near the coil array to which the spherical semiconductor is guided.
Preferably, the coil array is realized as a plurality of coil elements symmetrically arranged in the longitudinal and transverse directions on the given plane. The respective polarities and phases of the magnetic fields generated by means of the coil elements that constitute this coil array are individually controlled by means of the aforesaid magnetic field control element, whereby the respective directions of the magnetic fields in the region near the coil array to which the spherical semiconductor is guided are successively changed. Electric power supply and transmission and reception of the information signals can be securely carried out with use of a magnetic field in the direction corresponding to the posture of the spherical semiconductor.